Retrofit energy efficiency device and system to modify, manipulate and optimize airflow in vertical open-case refrigeration units

ABSTRACT

A method and apparatus for a retrofit energy device and system to modify, manipulate and optimize airflow in vertical open-case refrigeration units. An open refrigerated display case includes a refrigerated display area comprising one or more shelves, an air outlet and an air inlet opening into the display area and spaced from one another, and a duct configured to direct air flow out of the air outlet across the display area and toward the air inlet to form an air curtain across the display area, each one or more shelves provided

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit from U.S. Provisional Patent ApplicationSer. No. 62/399,535, filed Sep. 26, 2016. This prior application isincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

The present disclosure is generally related to open-case refrigerationtechnologies, and more specifically a retrofit energy device and systemto modify, manipulate and optimize airflow in vertical open-caserefrigeration units.

Retailers frequently use open-case refrigeration for some or all oftheir refrigerated items. Open-case refrigerators can be found invirtually every grocery store, supermarket, and convenience store aroundthe world. These units contain dairy, meats, prepared foods, perishablefood and beverages, keeping them cold while displaying them in a mannerthat is attractive and inviting to customers. One downside of verticalopen-case refrigerators is that as with all cooling devices, theyinherently use a lot of power, but in addition, their open fronts areextremely inefficient, resulting in high energy bills, losing on average75% of the energy used to operate it primarily due to infiltration ofwarm ambient air.

One prior method to overcome the deficiencies of vertical open-caserefrigeration units has been to use customized retrofit shelving toreplace the existing shelves which re-circulates air through a complexseries of channels built into them. However, this method employs aprocess that is both disruptive to retail operations and very costly toimplement due to its complexity.

Another prior method is to retrofit vertical open-case refrigerationunits with doors to achieve energy savings. However, opening a physicaldoor pulls cold air out of the case as it breaks the seal within therefrigerated space. For example, one study showed that when arefrigeration unit's door is opened over 60 times in one hour, itnegates any energy savings gained. On average doors reduce power used by25%, according to studies, while having a long payback of 5-7 years.

One major issue for retailers in determining power use and savings isthat most manufacturers test and develop their products in laboratoryconditions with stagnant air and no products on the shelves, which donot take into account the rigors and air movements that occur in thereal world from normal ambient activities. A person walking by avertical open case refrigeration unit can create warm air intrusion thatraises the temperature entering a Return Air Grill (RAG) by as much as50%, and can take as long as 30 seconds to recover. A full refrigerationunit responds differently to one that is half full.

Opening doors can also be cumbersome in high traffic areas or crowdedspaces, and hidden costs include elevated maintenance, as the doorsrequire frequent cleaning and the windows need de-fogging technologies,which use more energy. There is also a substantial cost and disruptionto retail operations associated with retrofitting open-caserefrigeration units with doors. Furthermore, some studies have shownthat placing a physical barrier between the customer and the productleads to reduced sales, and this loss negated the energy savings thatthe doors provided. Commercial retailers therefore still make extensiveuse of open refrigeration units despite their substantialinefficiencies.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the innovation in orderto provide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is intended toneither identify key or critical elements of the invention nor delineatethe scope of the invention. Its sole purpose is to present some conceptsof the invention in a simplified form as a prelude to the more detaileddescription that is presented later.

The present invention provides methods and apparatus for a retrofitenergy device and system to modify, manipulate and optimize airflow invertical open-case refrigeration units.

In one aspect, the invention features an open refrigerated display caseincluding a refrigerated display area comprising one or more shelves, anair outlet and an air inlet opening into the display area and spacedfrom one another, and a duct configured to direct air flow out of theair outlet across the display area and toward the air inlet to form anair curtain across the display area, each one or more shelves providedwith an airflow device attached in front of an outflow point of the aircurtain.

In another aspect, the invention features a refrigeration systemincluding a display case having an open front for allowing accessthereto and being capable of having shelves arranged therein, coolingmeans arranged along the top of a refrigeration system, first airpassage means arranged for receiving air passing through the coolingmeans and carrying refrigerated air therefrom to the display case, andmeans for establishing an air curtain, said air curtain extendingsubstantially vertically across the opening in said display case,wherein one or more of the shelves is provided with an airflow deviceattached in front of an outflow point of the air curtain.

Embodiments of the invention may have one or more of the followingadvantages.

A retrofit airflow device and features for airflow manipulation that canbe attached onto most state of the art vertical open-case refrigerationunits in existence.

A retrofit airflow device located in front of the DAG reduces energywaste and warm air infiltration by maintaining a parallel ambient aircurtain that minimizes the mixing of cold and ambient streams whileproviding the cold curtain additional momentum to travel further withminimal disruption.

A retrofit airflow device that can be attached to one or more individualshelves and create separation between the interior cavity of the shelfand the DAG air curtain flow and ambient air, thus creating a moreenergy efficient seal.

A retrofit solution where when the DAG area airflow device and shelvingairflow devices are deployed, both combined improve the overall energyefficiency of the vertical open-case refrigeration system.

A retrofit solution that can be configured to create separation of thecold air inside the shelves and the warm ambient air without a creatinga physical barrier between the product and consumer that can negativelyimpact retail sales.

A retrofit solution that does not require replacement of existingshelving or other parts of the original refrigeration unit, which canaffect cost, time for installation and potentially negatively impact theopen case refrigerators original manufacturer's warranty.

A retrofit solution which may use state of the art smart thermostatsystems to assist in optimizing the improved cooling environment insidethe shelving cavities.

A retrofit solution which can overall reduce the temperature of theshelves by improving the overall efficiency of the host vertical opencase refrigeration unit.

A retrofit solution that may use simple blocking methods to reduce theair volume being released from the rear of the shelves to reduceoverflow of cold air at the intake of the refrigerator case dischargeair grill (RAG).

A retrofit system that can plug directly into a wall plug using standardpower converters to eliminate the need for costly electrical installers.

A retrofit solution that targets the reduction in the number and lengthof the cooling cycles and the duty cycle of the host refrigeration unitto reduce its operating time and thus its energy use.

A retrofit solution that by reducing the operating cycles of verticalopen-case refrigeration units can extend the operating life of theseunits.

A retrofit system that uses airflow speeds between 0.3 m/s to 3 m/s onaverage to operate and can be modified to meet a host refrigerationunits specific operating parameters.

A retrofit solution that uses one or multiple low-power cross flowimpeller fans or blower wheels which are housed in retrofit deviceswhich are designed to optimize the airflow they generate and can bemanipulated in velocity, density and direction to meet the operatingparameters of its host refrigeration unit.

A retrofit solution which can be configured with other passive methodsto stabilize and optimize airflow.

A retrofit solution which in some cases effectively reduces thedifference in air temperatures between the RAG and DAG to as little asunder 1 degree C., allowing the condenser to not use as much power toaccomplish a reduction in the air temperature.

A retrofit housing that can be easily opened to access and replace aremovable motor that operates the airflow impellers.

A retrofit housing that can be easily opened to access and replaceremovable airflow impellers in the event of damage.

A new vertical open case refrigeration design can integrate thefundamental operating parameters that are being accomplished by thevarious airflow devices, features, configurations, signature airflowpatterns and characteristics of this invention.

These and other features and advantages will be apparent from a readingof the following detailed description and a review of the associateddrawings. It is to be understood that both the foregoing generaldescription and the following detailed description are explanatory onlyand are not restrictive of aspects as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood by reference to the detaileddescription, in conjunction with the following figures, wherein:

FIG. 1A is a diagram of a side view of an illustrative state of the artvertical open-case refrigerator after the compressor cycle activates(turns on) and it releases cold air from its air curtain to sustain itstemperature.

FIG. 1B is a diagram of a side view of an illustrative state of the artvertical open-case refrigerator after the compressor cycle activates(turns on) as it releases cold air from its air curtain with attachedairflow device(s) in accordance with an embodiment of the presentdisclosure.

FIG. 2A is a computer modeling (CFD) showing cold air loss and ambientair infiltration from an illustrative state of the art verticalopen-case refrigerator as the compressor cycle activates and releasescold air from its air curtain.

FIG. 2B is an illustration of a thermal image of a state of the artvertical open-case refrigerator as the compressor cycle activates andreleases cold air from its air curtain with an airflow device of thisinvention attached in accordance with an embodiment of the presentdisclosure.

FIG. 3A is a diagram of a side view of an illustrative state of the artvertical open-case refrigerator with cold air being released from itsair curtain at the top and from the rear of the shelving units.

FIG. 3B is a diagram of a side view of an illustrative state of the artvertical open-case refrigerator with cold air being released from itsair curtain at the top and from the rear of the shelving units. It alsoshows airflow devices of this invention attached at the entry point ofthe air curtain and on the ends of the individual shelves in accordancewith an embodiment of the present disclosure.

FIG. 4 is an illustrative side view of a state-of-the-art verticalopen-case refrigeration unit with one embodiment of this inventionshowing airflow devices of this invention attached at the entry point ofthe air curtain and on the penultimate/last shelf.

FIG. 5 is an illustrative side view of a state-of-the-art verticalopen-case refrigeration unit with another embodiment of this inventionshowing airflow devices of this invention attached at the entry point ofthe air curtain and on the penultimate/last shelf, and retractable doorsacross the opening of the last shelf.

FIG. 6 shows an illustration of an enhanced IR image of the side of thevertical open case refrigerator unit with embodiment of FIG. 3A, showingflow of the air curtain spilling over the bottom of the open area of theunit.

FIG. 7 shows an illustration of an enhanced IR image of the side of thevertical open case refrigerator unit with embodiment of FIGS. 4 and 5,showing further improvement in air curtain shape and performance.

FIG. 8 is a diagram of a side view of an illustrative airflow device andhousing in accordance with an embodiment of the present disclosureattached next to the DAG area of a vertical open-case refrigerator unit.

FIG. 9 is a diagram of a side view of an illustrative airflow device andhousing in accordance with an embodiment of the present disclosureattached to the end of a shelf of an open-case refrigerator.

FIG. 10 is a diagram of a perspective view of an illustrative airflowdevice in accordance with an embodiment of the present disclosureattached to the end of shelf of a vertical open-case refrigerator. Itshows the air intakes and outflows.

FIG. 11 is a diagram of a perspective view of an illustrative airflowdevice in accordance with an embodiment of the present disclosureattached to the end of multiple shelves of a vertical open-caserefrigerator. It shows that the airflow devices extend along thehorizontal length of the front of each shelf.

FIG. 12 is an illustrative perspective view of one possible embodimentof an airflow device and housing of the present disclosure illustratingvarious component of the airflow device.

FIG. 13 is an illustrative perspective view of one possible embodimentof an impeller of an airflow device of the present disclosureillustrating various component of the impeller.

FIG. 14 is an illustrative perspective view of one possible embodimentof a removable and replaceable electrical motor connected to an impellerof an airflow device of the present disclosure illustrating theassembly.

FIG. 15 is an illustrative perspective view of one possible embodimentof a removable and replaceable flow conditioner used in an airflowdevice of the present disclosure illustrating the features and detailsthereof.

FIG. 16 is an illustrative perspective view of one possible embodimentof the doors used as part of the present disclosure illustrating thefeatures and details thereof.

FIG. 17A is an illustrative side view of one possible alternativeembodiment of the invention of the present disclosure showing the use ofan air vent duct instead of a Shelf Fan to redirect air into the RAGarea.

FIG. 17B is an illustrative side view of one possible alternativeembodiment of the invention of the present disclosure showing thedetails of the air vent duct.

FIG. 17C is an illustrative perspective view of one possible alternativeembodiment of the invention of the present disclosure showing thedetails of the air vent duct.

DETAILED DESCRIPTION

The subject innovation is now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It may be evident, however, thatthe present invention may be practiced without these specific details.In other instances, well-known structures and devices are shown in blockdiagram form in order to facilitate describing the present invention.

In addition, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A, X employs B, or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. Moreover, articles “a” and “an” as used in thesubject specification and annexed drawings should generally be construedto mean “one or more” unless specified otherwise or clear from contextto be directed to a singular form.

The present invention provides a compact energy efficiency device andsystem to modify, manipulate and optimize airflow in order to reduceenergy use in open-case refrigeration units by creating a specificairflow characteristic and shape pattern. More specifically, theobjectives of this device or devices are to produce a balancedcombination of particular airflow pattern characteristics, optimize,redirect, change velocity and strengthen the airflow within state of theart vertical open case refrigeration units. Since the airflowcharacteristics are unique, the application can be universally appliedacross a diverse number of vertical open case refrigeration designs andmanufacturers, including both new and retrofit applications.

Individual impacts of this invention include the reduction of warm airintrusion by improving the recovery time strengthening the air curtainnear the Discharge Air Grill (DAG) and upper half of the open caserefrigerator; using a secondary airflow device reducing cold air lossfrom the host air curtain by redirecting it and optimizing the velocityas it approaches the final shelf prior to the RAG; producing a signatureairflow pattern; reduce the volume of warm air intrusion into the RAG bystrengthening the curtain near the intake using passive or activedevices. By reducing the temperature of the air entering the RAG, thehost unit's compressor does not need to expend as much power and operatefor as long a period to reduce the air temperature being released at theDAG.

Systems according to the present disclosure can help to reducesubstantial energy costs exhibited by prior-art vertical openrefrigeration units or display cases in retail establishments. The costreductions can be very significant given the large numbers of units inoperation and the high levels of energy that they consume. These costreductions can result from better containment of the cold air, optimizedairflow patterns and reduction of the intrusion of the warmer ambientair, which reduces the power consumption of the unit to maintain itsoptimal operating temperatures.

To put the potential cost savings into perspective, most people considerthe cost of air conditioning a home one of the largest electricityexpenses, and a typical 1000 square foot (sf) home can be cooled with a1 ton air conditioner which uses about 1000 watts to operate it. Incontrast, a typical 4 foot length, state of the art vertical open caserefrigeration unit will use 1,300-1,600 watts to power it. A typical1,000 sf convenience store in most countries will contain 40 linear feetof open case refrigeration. So the cost of powering an open caserefrigeration system is over ten times the cost of air conditioning thesame space.

FIG. 1A is a diagram of a side view of an exemplary vertical open-caserefrigerator after the compressor cycle activates. The air circulatesthrough the refrigeration unit 100 as it is cooled and is slowlyreleased through the outflow point of the air curtain Discharge AirGrill (DAG) 101. Simultaneously, air is released from the rear panels102 of the refrigeration unit, which cools the product placed in thecavity of the shelving. As the air is released from the air curtain itmixes in with the warmer ambient air 103 as it gradually organizesitself to eventually create a more stable downward motion to help sealthe open cavities of the shelves. As the cold air moves towards theopening of the shelves, it continues flowing in an outward and downwarddirection 104. At the bottom of the unit, there is an inputReturn/Receive Air Grill (RAG) 105 where the air is re-captured andcooled before it is released to the shelves and the DAG 101. Theinefficiency of the system creates a substantial overflow of cold air106 which is a large portion of the energy loss.

FIG. 1B is a diagram of a side view of an exemplary vertical open caserefrigerator after the compressor cycle activates as it releases coldair from its air curtain. In this illustration, an airflow device 110 ofthe present invention is attached in front of the outflow point of theair curtain DAG. 111 The speed of the airflow 112 from the airflowdevice must be matched or similar to the airflow speed 113 beingreleased from the refrigeration unit's air curtain (DAG) to avoid shear,which will result in warm air intrusion. As the upper airflow device ofthis invention is active in perpetuity, it substantially reduces thelosses associated with state of the art vertical open-case refrigerationsystems due to cold air spillage and warm air infiltration, bystrengthening the existing air curtain and in the event of warm airintrusion, a much faster temperature recovery time, often in half thetime. Airflow from the air curtain is immediately contained and theresult has been that the air entering the RAG 114 is colder, whilereducing the cold air overflow 115. Temperatures being released from theDAG 111 are colder as are the individual temperatures in the shelvingspaces using this type of airflow management system using the devices inthis invention. In case studies, the difference between the RAG and DAGhas been as little as under 1 degree Centigrade (C).

FIG. 2A is an illustrative computer modeling (CFD) showing cold air lossand warm ambient air infiltration from an illustrative state of the artvertical open-case refrigerator, as the compressor cycle activates andreleases cold air from its air curtain 200. As the airflow attempts toorganize, substantial losses of cold air occur 201, while facilitatingwarm air infiltration 202 which is shown as a lighter shade entering theRAG 203.

FIG. 2B is an illustration of a thermal image of an exemplary verticalopen-case refrigerator as the compressor cycle activates and releasescold air from its air curtain with an airflow device 210 attached inaccordance with an embodiment of the present disclosure. The cold aircurtain is seen to be pushed inwards such that half 211 of the curtainis getting sucked back into the RAG, while the other half 212 spillingout of the unit due to watershed effect from the back panel flow 213bottom two shelves.

FIG. 3A is a diagram of a side view of an exemplary vertical open-caserefrigerator with cold air being released from its air curtain 300 andfrom the rear of the shelving units 301. As the air curtain from the DAG300 descends it tends to move outwards allowing a greater mixing of coldair 303 with ambient warm air towards the bottom of the unit. The lessorganized the air curtain, the greater the infiltration of warm ambientair. The state of the art open nature of individual shelves releasessubstantial volumes of cold air, which then adds to the overflow at theentry point of the RAG 304. A clearer diagram of this shape and effectis illustrated in FIG. 6

FIG. 3B is a diagram of a side view of an exemplary vertical open-caserefrigerator with cold air being released from its air curtain 310 andfrom the rear of the shelving units 311. It also shows airflow devicesof this invention attached at the entry point of the air curtain 312 andon the ends of the individual shelves 313 in accordance with anembodiment of the present disclosure. The airflow from the device infront of the air curtain outflow 314 is shown containing the airflowfrom the air curtain 315 and creating separation. The airflow deviceslocated at the end of the shelves 313 improve the containment of the airinside each shelf cavity, reducing the overflow 316 and improving thecooling of products on each shelf. The reduction of overflow from theshelves will reduce the overflow and mixing of cold air going into theRAG 317.

In laboratory environments, the strengthening of the cold air curtainwith an airflow device of this invention does a good job of containingthe top 3 shelves. Individual shelf fans for these shelves althougheffective may be cost prohibitive if the marginal power savings doesn'tjustify the additional cost of materials and installation.

FIG. 4 shows an alternate embodiment of the current invention which incertain cases optimizes the energy gains against theproduct/installation cost. This embodiment uses only two airflowdevices. One airflow device 401 near the top of the unit intakes ambientair and creates an airflow 402 that runs parallel to the cold aircurtain 403 created by the DAG 404. The DAG airflow has matching orsimilar velocity to that of the cold air curtain. This velocity matchingor similar speed reduces shear between the curtain and the airflowgenerated by this invention and reduces the mixing between cold and warmair temperatures. The second airflow device 405 is attached at the outeredge of the penultimate/last shelf 406, which intakes the cold air 407being discharged from the rear panel of that shelf as well as thecompacted cold air 408 descending from the main cold air curtain. Thisfan re-directs these two streams and infuses the cold air 409 anddirects it towards the RAG 410. This has the combined effect of pushingthe slightly warmer air away from the RAG (since cold air is denser) andreplacing it with colder air, thus reducing the temperature of the air411 going into the RAG. The shelf fan also relieves some of the outwardpressure created by the back flow and reduces the watershed effect whichpushes the main curtain 403 outwards in other state of the art unitsthat are not fitted with the devices of this invention. The inventors ofthis disclosure have observed and demonstrated this effect via infraredvisualization techniques. The effect of this and the airflow shape itproduces is clearly is illustrated in FIG. 7.

The inventors of the current disclosure have further observed that mostof the cold-and-warm air mixing happened very close to the RAG, roughlyacross the vertical height of the last shelf. This is expected since theintegrity of the DAG cold air curtain starts disintegrating beyond thethird shelf, (unless re-directed by a secondary shelf fan) and thecumulative back flow from the previous shelves creates a watershedeffect pushing the cold air curtain outwards thus compromising itsintegrity.

FIG. 5 shows another embodiment of the current invention that improvesupon the embodiment of FIG. 4. The embodiment of FIG. 4 still allowssome warmer air 412 to get into the RAG. The embodiment of FIG. 5virtually eliminates this problem by introducing a physical barrier inthe form of a see through door 512 across the opening of the bottomshelf all the way to the RAG outside edge. This ensures that the RAGonly receives the cold air 509 from the shelf fan 505 installed on thepenultimate/last shelf 506, thus further reducing the final temperatureof the air 511 entering the RAG 510. As a result of this, during theperiod when the compressor is in the off cycle, the difference betweenthe RAG and DAG temperatures would go as low as under 1 degreecentigrade in our testing compared to observed numbers as high as 6-8degrees C. differential in baseline tests.

The arrangement of FIG. 5 uses two airflow devices 501, 505. Forpurposes of easy identification, these are called the DAG Fan and theShelf Fan, respectively. The DAG Fan 501 is attached close to the DAG504 towards the outer end of the unit. This fan draws in warm ambientair and creates a parallel thinner airflow running alongside the defaultcold curtain of the unit. To facilitate this, the DAG Fan has air intakedesigned facing outside the unit. The horizontal location of the RAG 510varies depending on the design of the refrigeration unit and hence theRAG may not always be vertically aligned with the DAG. To accommodatefor these differences, the DAG Fan is mounted near the DAG with bracketsthat allow for adjusting the angle of the warm airflow duringinstallation.

The Shelf Fan 505 is installed at the outer edge of the penultimate/lastshelf 506. It draws and re-directs the cold air 508 descending from theDAG curtain 503 and combines with the colder air 507 coming from theback panel of the penultimate/last shelf. To facilitate this, the ShelfFan has an air intake directed towards the top edge of the shelf it isinstalled on. This combined cold air is then directed towards the RAGentrance. The location of the RAG entrance varies depending on thedesign of the refrigeration unit. To accommodate these differences, theShelf Fan is mounted to the shelf with brackets that allow for adjustingthe angle of the resulting curtain during installation.

FIG. 6 shows the shape of the DAG curtain of a state of the art verticalopen case refrigeration unit showing an illustrated version of infrared(IR) imaging without any of the embodiment of the current invention. Thewatershed effect is clearly seen as the cold curtain flares outwards asit descends vertically. This airflow shape and characteristicillustrated here is typical of current state of the art vertical opencase refrigeration units.

FIG. 7 in stark contrast to FIG. 6, this illustrated version shows theshape of the DAG curtain as evinced by IR imaging with the embodiment ofFIGS. 4 and 5. It is seen that the cold curtain shape is drasticallyaltered. The curtain is clearly seen to be pulled inwards near thefourth shelf due to suction by the shelf fan. Overall the curtaindescends more or less vertically without much dispersion/flaring,resulting in lower warm air infiltration and better refrigerator powerperformance. This airflow shape which is easily determined using thermalimaging, defines the objectives of this invention using the variousdevices and features described in this invention. By duplicating thisshaping, the power savings principles described in this invention can bebroadly applied.

FIG. 8 is a diagram of a side view of an illustrative retrofit DAG areaairflow device housing 801 in accordance with an embodiment of thepresent disclosure attached near the DAG 802 of a state of the artvertical open-case refrigerator. In this iteration, the airflow device801 is attached outwards of the DAG 802 by one of multiple commonlyknown methods including clips, strap, brackets, and bolts among others.Using one or multiple low power consumption cross flow fan impellers orblower wheels 803, ambient air 808 is pulled from the perforated/slottedintake 804 and forced out in a thin layer of air 805 parallel to thecold air curtain 806 to create containment. A flow conditioner such ashoneycomb shaped material 807 enables the flow coming out of the airflowdevice to be laminar and coherent. The voltage of this unit may beincreased or decreased to optimize the velocity released by the device,and thus the volume of air moved.

FIG. 9 is a diagram of a side view of an illustrative Shelf Fan airflowdevice in accordance with an embodiment of the present disclosureattached to the end of the shelf/shelves of a vertical open-caserefrigerator. The airflow device 901 housing is attached to the end ofthe shelf/shelves 902 by one of multiple commonly known methodsincluding clips, strap, brackets, and bolts among others. Using one ormultiple low power consumption cross flow impeller fans or blower wheels903, air 904 is pulled from the upper part of the shelf via aperforated/slotted intake 905 and forced out in a thin layer of air 906across the bottom shelf to create containment. A flow conditioner suchas a honeycomb shaped material 907 ensures the flow coming out of theairflow device is laminar and coherent. Since the shelf is beingextended over the existing product price code, the airflow device can bemounted with its own product price code holder 908.

FIG. 10 is a diagram of a perspective view of an illustrative Shelfmounted airflow device 1001 in accordance with an embodiment of thepresent disclosure attached to the end of shelf of an open-caserefrigerator. It shows the perforated air intake 1002 which captures airacross the horizontal surface of the shelf and generates outflows 1003.The product price code attachment 1004 on the airflow device is shown.

FIG. 11 is a diagram of a perspective view of an illustrative shelfmounted airflow device in accordance with an embodiment of the presentdisclosure attached to the end of multiple shelves 1101 of a verticalopen-case refrigerator. It shows that the airflow devices 1102 extendalong the horizontal length of the front of each shelf. The thin airflow1103 being released vertically along the horizontal length of the frontof each shelf has a secondary effect of reducing the overflow out of thecavity from each shelf by creating separation between the interior ofthe shelf and the exterior of the shelf. This reduces the horizontalpressure on the air curtain. Additionally, as the airflow device intakesair at the bottom of each shelf, it also reduces the overflow byre-directing it downwards. The airflow devices of this invention havewiring 1104 to be attached to a power source which may be DC or AC anddue to the low power usage required by these devices, may be powered bysolar panels or batteries.

FIG. 12 shows the general design details of an airflow device used togenerate airflow needed for this invention. The device consists of ahousing 1201, single or multiple crossflow impellers 1202, an electricalmotor 1203 that is preferably removable/replaceable, a flow conditionersuch as a honeycomb shaped device 1204 which is also preferablyremovable and replaceable, and electrical connectors 1205. The airflowdevice assembly can be of a modular design facilitating quick assemblyand replacement of individual components/modules. The housing has aperforated/slotted panel 1206 that acts as an air-intake whileprotecting the impeller/s 1202 from undue exposure or intrusion. Thehousing can have access panels that can be flipped open or removed toprovide internal access for repair and maintenance. The housing hasmounting features for snap-fit of impeller bearings such that theimpellers can be individually put in or taken out with ease forreplacement. The housing units containing the airflow devices can bedesigned to connect to another housing in parallel to run longer lengthsof vertical open case refrigeration units which may be installed in aninterconnected configuration. The housing units containing the airflowdevices may also be connected vertically to simplify installation.

FIG. 13 shows the general design of the impellers used in the airflowdevice of FIG. 12. The impellers consist of prefabricated assembly 1301made of metal, plastic, composites, or any combination thereof. Theimpeller has a male shaft 1302 at one end and a female hole 1303 at theother end. The impeller shaft rotates inside a bearing 1304 whichprovides for lubrication and support to the impellers. The impellershave flexible mating features on one end to couple it to the neighboringimpeller while allowing for axial tilt during assembly/replacement.

FIG. 14 show the electrical motor. The electrical motor 1401 driving theimpeller assembly 1402 is of brushed or brushless type, rated for 6-2 V,0.1-0.25 A, and 2000-4000 rpm in one embodiment. The motor is coupled tothe impeller assembly by a coupling 1403 housed inside a mountingfeature in the housing. A motor mount integral to the housing allows fora snap-fit of the motor into the housing. As the motors have a knownfinite life of a few years, the motor mounting and coupling arrangementin one embodiment is designed for easy replacement of the motor. Themotor is electrically connected to the housing via removable male-femaleconnectors. The electrical connections consist of female sockets oneither end of the housing. The sockets may be of any design andstandard. Power is tapped from one of the sockets and supplied to themotor, while a wire running through the housing provides electricity atthe other socket for connecting another airflow device. The fans aresupplied with a 12v DC power via a wall-adapter, and have voltageadjustment devices inside the housing or on the power supply box foreasy adjustment of the operating voltage, and hence the air-curtainspeed.

FIG. 15 shows a flow conditioner 1501 which is preferably designed to beeasily replaceable and can be made of plastic, metal, or other manmadeor natural composite with specific geometric parameters. The purpose ofthe flow conditioner is to smoothen the flow coming out of theimpeller(s) and provide uniform laminar flow regardless of where it isreleased. The flow conditioner may have arrays of channels 1502 of anyshape and profile (including but not limited to square, rectangular,circular, hexagonal) in any pattern to achieve this. The dimensions ofthe flow conditioners are subject to change and may assume any valuedepending on the design of the refrigerator unit. The airflow devicecreates an air curtain that is approx. 10mm thick at exit and spans thelength of the device. In this iteration, the average velocity of the airat the exit of the flow conditioner is typically between 0.2 m/s and 3m/s, but may assume any value depending in the design of therefrigerator unit.

FIG. 16 shows the door/s used on the last shelf. The door/s consist ofrectangular panels 1301 of a transparent material (glass, plastics orother composites) in a single or multiple split configuration. Althoughnot necessary, the door/s may be attached to the shelf-fan or shelf viahinges 1302 or other similar flexible attachment at one end to allow foreasy retraction and closure. A handle 1303 is installed on the other endto allow easy opening and closing of the doors. The doors may or may nothave a slot 1304 running along most of its length to moderate flow. Thesize and location of the slot is not fixed and can assume any parametersdepending upon the refrigeration unit's flow characteristics. The doorsmay or may not be installed depending on customer discretion and mayalso be of the sliding type.

FIG. 17A shows one embodiment of the present disclosure whereby theShelf Fan is replaced with an air vent duct 1701 sitting between theedge of the shelf 1702 and the hinge 1703 of the bottom shelf door 1704.This air vent duct experiences some suction on account of the powerfulsuction at the RAG 1705 which is up to twice the velocity of the DAGairflow. In certain configurations, the RAG might provide enough suctionat the air vent duct to make a Shelf Fan unnecessary. The duct runsalong the entire width of the shelf, and the width of the duct isconfigurable based on the operating parameters of the particular unitthe invention of this disclosure is retrofitted on. A flexible sealattached to the shelf doors 1704 would reduce cold air loss whilestrengthening the pull of the RAG from the air vent ducts.

FIG. 17B shows the concept of FIG. 17A in closer detail. The gap 1711between the shelf 1712 and the hinge 1713 of the door 1714 forms an airvent duct, which experiences some suction on account of the powerfulsuction generated by the RAG. The width of the air vent duct 1711 isconfigurable based on the operating parameters of the particular unitthe invention of this disclosure is retrofitted on.

FIG. 17C shows the concept of FIG. 17A in further detail. The gap 1721between the shelf 1722 and the hinge 1723 of the door 1724 forms an airvent duct, which experiences some suction on account of the powerfulsuction generated by the RAG. The width of the air vent duct 1721 isconfigurable based on the operating parameters of the particular unitthe invention of this disclosure is retrofitted on.

The housing containing the airflow devices can be universallyretrofitted onto vertical open case refrigeration units by means ofbrackets, screws or other state of the art secure fastening methodavailable. The mounting brackets may have provisions to set the angle ofthe devices of this inventions airflow to an optimal degree duringinstallation to adapt to the design or configuration of therefrigeration unit and the characteristics of its airflow. Multiple fanscan be connected in series such that several linear feet of refrigeratedunits can be powered by just one or multiple power supply(s). Theindividual units may be daisy-chained together using patch cables thatelectrically connect them to each other using the electrical jacks onthe sides of the fans. The patch cables have male jacks on both endsthat plug into the female sockets on the airflow device housing. Giventhe low power usage of the fans of this invention, (in most casesbetween 1-2 watts per device) there is a possibility to operate themusing solar power arrays installed either inside or outside.

The retrofit solution presented in this invention includes thepossibility of incorporating it into new production units by suitabledesign modifications. The key to the success of this invention is thecharacteristic shape and airflow signature that pulls and re-directs thecold airflow from the air curtain in an inward angle towards the lastshelf which reduces the warm air infiltration at the RAG.

The DAG and Shelf Fan type devices of this invention with similaroperating parameters can be made integral to the new vertical open caserefrigerator unit with power supplied to the fan from within the unit'selectrical supply.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed is:
 1. An open refrigerated display case comprising: arefrigerated display area comprising one or more shelves; an air outletand an air inlet opening into the display area and spaced from oneanother; and a duct configured to direct air flow out of the air outletacross the display area and toward the air inlet to form an air curtainacross the display area, each one or more shelves provided with anairflow device attached in front of an outflow point of the air curtain.2. A refrigeration system comprising: a display case having an openfront for allowing access thereto and being capable of having aplurality of shelves arranged therein; cooling means arranged along thetop of a refrigeration system; first air passage means arranged forreceiving air passing through the cooling means and carryingrefrigerated air therefrom to the display case; and means forestablishing an air curtain, said air curtain extending substantiallyvertically across the opening in said display case, wherein one or moreof the plurality of shelves is provided with an airflow device attachedin front of an outflow point of the air curtain.
 3. A system comprising:an airflow device attached in front of an outflow of an air curtain of arefrigeration unit that reduces energy waste and warm air infiltrationby directing a flow downward, using an airflow speed similar to that ofthe refrigeration unit.
 4. A system comprising: a refrigeration unit;and a retrofit solution system attached to one or more individualshelves of the refrigeration unit that creates separation between aninterior cavity of the individual shelf and an air curtain flow andambient air, creating an efficient seal.
 5. A system comprising: an openrefrigerated display; and one or more airflow devices that createsseparation of cold air inside one or more shelves and warm ambient airwithout creating a physical barrier between a product on the one or moreshelves and an exterior of the open refrigerated display.
 6. A retrofitairflow device designed to attach to the inside or outside of an opencase refrigeration unit, the airflow device comprising a housingcontaining single or multiple crossflow impellers, an electrical motor,a flow conditioner such as a honeycomb and electrical connectors, eachof these components replaceable for easy maintenance or repair, whoseair flow speed can be modified to match various specifications, theairflow devices designed to connect to another housing in parallel torun longer lengths of vertical open case refrigeration units which maybe installed in an interconnected configuration.
 7. A retrofit air flowdevice which has been designed to be easily modified to attach to anypen case refrigeration shelves.